Reactive melt spinning of linear polyamide 6 via self-initiated anionic polymerization.

[Display omitted] • Linear polyamide 6 was synthesized through the simplest self-initiated anionic polymerization. • The polymerization products exhibit highly consistent properties comparable to commercial spinning grade polyamide 6. • In this paper a novel fiber forming method is proposed called reactive melt spinning. • The polyamide 6 micro-nano fiber materials were directly fabricated from ε-caprolactam monomer in one step. Polyamide 6 (PA6), as a well-established engineering thermoplastic, plays a crucial role in modern society. However, the traditional production mode of PA6 has many drawbacks such as complex processes, huge energy consumption and serious pollution, and it is often separated from the processing technology. Here we report a simple and efficient method for synthesizing linear PA6 polymers, i.e., self-initiated anionic polymerization of ε-caprolactam. It was found that a high conversion rate of over 94 % was achieved at 240 °C for 15 min using sodium hydride as a catalyst only. The polymerization products thus obtained exhibited characteristics consistent with those of commercial spinning grade PA6. Furthermore, we successfully prepared PA6 micro-nano fiber materials by seamlessly integrating the two processes of linear polyamide 6 synthesis and melt spinning. This innovative reactive melt spinning technology is expected to create a new situation in the preparation and application of high-performance fibers. [ABSTRACT FROM AUTHOR]